Part I. Isolation and identification of sesquiterpenoids from Cupressus bakeri. Part II. A synthetic approach towards crotonitenone.

摘要

Part I discusses sesquiterpenoids from the foliage of Cupressus bakeri. Six new sesquiterpenoids (CB-M182, -1B, -2A, -6, -7, and -9) have been isolated from the essential oil of the plant. CB-M182 is recognized as a trisnor-cadinane-type sesquiterpenoid. Bakerol (CB-1B) possesses a new spiro-fused carbon skeleton probably generated by ring contraction of an acorane-type precursor. The structures of these new compounds were assigned by means of chemical and spectral studies. The relative configurations were established based on the extensive 2D NOESY experiments. Statistical correlations and probable biosynthetic pathways for the identified compounds are also presented.; Part II describes synthetic efforts toward the synthesis of a natural diterpenoid, crotonitenone. TBDMS protecting group attached phosphonium salt 33 has been produced by high pressure reaction in high yield (70%). A key reaction is a Wittig reaction of the salt 33 with hydroxy lactone 34 and attempts to increase yield for the Wittig reaction are examined.